Welcome to my latest thought experiment. Play is natural, work is not.
I have decided that play is a natural positive activity for humans and this can be shown in part by comparing it with the other natural positive activities of humans, of which I have come up with four. These four are based on what I can think of as the only things humans want to do and enjoy doing - beyond the fact that they contribute to a healthy life. These four are eating, sleeping, having sex, and playing.